Automatic firearm



May 23, 1939.

M. BIRKIGT AUTOMATIC FIREARM .Filed April 16, 19:58

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Patented ay 23, 1939 2,159,126 AU'ro'MA'rro FIREARM Marc Birkigt, Bois-Colombes, France Application April 16, 1938, Serial No. 202,545 In Belgium February 11, 1938 4 Claims.

The present invention relates to automatic firearms and in particular, but not exclusively, light guns for use on aircrafts.

In guns of the type with which the present 5 invention is concerned, the tube of the arm is provided at the rear with a movable breech system adapted to recoil when a shot is red, against the action of. a counter spring, and to be locked, at least partly, when brought back into firing 0 position. Usually, this movable breech system includes a breech block proper adapted to close the tube and hold the cartridge rmly in the chamber thereof, when' locked in said firing position, and a sliding part, carrying the firing pin,

5 normally locked to the breech block when the latter is not locked in firing position and adapted to further move in the forward dircctionwith respect to said breech block after the latter has been locked, under the eiect of the counter spring `0 and also of inertia, 'whereby the ring pin is caused to strike the cartridge.

In guns of this type, when the gun is not to nre, the whole of the movable breech system i's locked in its rear position, corresponding to the 5 beginning of the return stroke thereof.

The object of the present invention is to provide a breech mechanism of lthe type -above referred to which is better adapted to meet the requirements of practice than mechanisms used 0 up to the present time for the same purpose.

According to the essential feature of the present invention, the sear or equivalent part adapted to hold the movable breech system in the rear position thereof, so as to stop the working of 5 the firearm and to control the action thereof, cooperates with the locking member, carried by the movable breech system, which locks said breech system in the forward or firing position thereof.

D Other features of the present invention will result from the following detailed description of a specific embodiment thereof.

A preferred embodiment of the present invention will be hereinafter described, with reference 5 to the accompanying drawing, givenmerely by way of example, and in which:

Fig. 1 is an elevational view, partly in axial vertical section, showing the breech mechanism of an automatic firearm made according to the present invention; y

Fig.. 2 is a similar view of the same mechanism, with the parts occupying dilerent relative positions, corresponding' to another time of operation;

Fig. 3 is a sectional view on the line III- III Fig. 4 is a vetical section on the line IV-IV of Fig. 1; v

Fig. 5 is a Vertical section on the line V-V of Fig. 2.I

In the embodiment of my invention, illustrated by the drawing, at the rear of the barrel or tube I, the structure of which has no bearing upon the present invention, a breech casing 2 is rigidly fixed. This casing 2 acts as a guide for the movable breech structure which will be described later. Casing 2 is` provided with a cartridge feeding slot 3 and a diametrally opposed slot li for the ejection of the cartridge cases.

yThe movable breech structure which is slidable in said casing 2 is urged frontwardly by a counterspring 5, toward the position in which it closes the rear end of the barrel or tube.

In the embodiment described by way of example, this movable breech structure is made of two parts slidable relatively to each other in the direction of the general sliding displacement of the whole.

One'of these two parts is constituted by the breech block proper 6, that is to say the part which forces and wedges the cartridges into the chamber of the barrel or tube of the gun.

The other part 8, movable longitudinally with respect to said breech block, carries the firing pin 9. Y

The breech block 6 carries, pivotally mounted thereon, at the lower part, a pawl 1 for the locking of said breech block, and said pawl is made of a material as hard as possible, for instance casehardened steel.

This pawl is adapted to oscillate between two extreme positions, which will be called hereinafter the upper position (Fig. 2) and the lower position (Fig. l.)

When pawl 1 is in the upper position, it interconnects the breech block 6 with the other breech element 8, this postiion being that occupied by the parts as long as the breech block is at the rear of its firing position.

On the contrary, when pawl 'l is in its lower position, it locks the breech block with respect to casing 2 as soon as said breech block reaches its firing position, so that said block is stopped in said position. The other breech element, to with 8, which carries striker -9, is then free to move alone toward the cartridge, this supplementary o displacement being made possible by the provision of an elongated passage 6' in the breech block 6 and being produced by the. action of the counter spring '5. This movement corresponds to the percussion of the cartridge which, at this time is d panyine claims.

being securely held in the tube chamberbythe breech block 6.

I further provide. means for imparting a recoil movement to breech element 8 after each shot has been fired. In. the example shown by the drawing, the means in question consist of a cyl-| inder and piston system the movable element II of which is rigid with a push piece I2 adapted to act on said element 8.

This relative movement of element 8 with respect to the breech block 6 brings a recess provided in the lower part of element 8 above the end of pawl 8, so that When, under the effect of the reaction of the powder gases, pawl I3 tendsV to pivot upwardly (owing to the upward component produced by inclined surface I3), said pawl can engage into said recess, thus unlocking the whole of the breech structure from the breech casing, and permitting the rearward movement of said breech structure, the elements 6 and 8 of which are now interlocked by pawl 1 engaged in the above mentioned recess of element 8.

In order toprevent the gun fromv ring, the whole of the breech structure is held in its rear position by the following means:

A sear or cat'ch I4 carried by the breech casing is arranged normally to project into the inside of said casing so as to engage With the breech structure and to stop it at the beginning of its return stroke. This rcatch is normally urged toward this stopping position by a spring pushpiece I5 slidable transversely in the breech casing. Control means for releasing the breech structure from this locking action are constituted, in the example disclosed by the drawing, by a stirrup I6 operative by means of a cable I1. When said cable is pulled, the gun starts firing, and as soon as the cable is released, thev ring stops.

"According to the essential feature of the present invention, the nose I4 of this sear or catch I4, instead of cooperating directly with the breech block, as it was the case up to the present time, engagesinto a notch, or the like, I8 provided in pawl 1, preferably in the rear middle portion thereof.

The chief advantage of this arrangement is that the re control systemis particularly strong because the Stopping of the breech structure in the rear position is ensured by the cooperation of two elements (1 and I4) both of which are made of particularly hard metal (since catch I4 is generally made, likepawl 1, of case hard-v ened steel).

Furthermore, when notch I8 nally becomes deteriorated by wear and tear, it sumces to change the locking pawl r1, instead of having to change the Whole of the breech block.

In a general manner, while I have, in the above description, disclosed what I deem to be practical and keiicien't embodiments of the present invention, it should be well understood that I do not Wish -to be limited thereto as there might be changes made in the arrangement, disposition, and form of the parts Without departing from the principle'ofithe present` invention as comprehended within the scope of the accom- What I claim is:

1. An automatic firearm which comprises, in combination, a tube, a breech structure movable with a longitudinal reciprocating motion in line with said tube at the rear thereof, a stationary guide for said breech structure rigid with said tube, a pawl pivoted to said breech sturcture adapted to cooperate with said guide for locking said breech structure in the front position thereof with respect tosaid tube, and lockingv means carried by said stationary guide adapted to cooperate with said locking pawl for holding said breech structure temporarily in rear position in said guide.

2. An automatic firearm which comprises, in combination, a tube, a breech structure movable with a longitudinal reciprocating motion in line with said tube at the rear thereof, a stationary casing with said tube for guiding said breech structure, said breech structure including a breech block and a firing pin carrier movable to a. limited extent with respect to said breech fblock, a pawl pivotedto said breech block adapted to cooperate with said casing for locking said breech block in the front position thereof with respect to said tube, said pawl being further adapted to lock said breech block with said ring pin carrier when said breech block is loing a breech block and a tiring pin carrier movable to a limited extent with respect to said breech block, a pawl pivoted atits front part to said breech block adapted to cooperate alternately with said casing when said breech block is in the front position for locking it in said poy,sition, and with said ring pin carrier for locking the latter with said breech block when said breech block is behind said front position, a pawl movably carried b'y said stationary casing adapted to cooperate with said rst mentioned pawl for locking said breech structure temporarily in rear position with respect to said -sta'tionary casing, and means for controlling said second mentioned pawl.

4. An automatic rearm which comprises, in combination, a tube, a breech structure movable with a longitudinal reciprocating motion in line with said tube at the rear thereof, a stationary casing rigid with said tube for guiding said breech structure, said breech structure including a breech block and a firing pin carrier novable to a limited extent with respect to "said breechr block, a locking pawl pivoted at its front end to said breech block'adapted to cooperate alternately with said casing when said breech f block is in the front position f or locking it in said position, and with said firing pin carrier for locking the latter with respect to said breech block when said breech block is at the rear -of said front position, said pawl being provided with a notch in its intermediate portion; a catch y movably carried by said stationary casing so as to be able to engage into said notch for locking said breech structure. temporarily in rear position with respect to said casing; and means for)- controlling said catch,-` fo MARC BIRKIGT. 

